As is well known in the plumbing trade, pipes and other fluid conduits are subject to eventual damage due to corrosion, freezing or other causes. Additionally, it is necessary from time to time to tap into existing plumbing to provide additional fluid lines for system additions. Whatever the reason, when an existing fluid conduit or pipe must be opened for repair or other reasons, the fluid upstream must be shut off in order to permit the required work to be accomplished.
When this fluid is shut off, obviously other fluid lines from between the shutoff point and the repair location cannot be used. Accordingly, it is often desirable to block the conduit or pipe immediately upstream of the repair, to allow fluid to flow to that and other points upstream of the repair. Another advantage of the complete blockage of the fluid line is that there will generally be at least some residual fluid flow in the line, even after a shutoff valve is closed upstream. If heat is to be applied to the pipe (e.g., soldering with a torch or other tool) the fluid will likely preclude the development of sufficient heat to perform the operation, particularly in the bottom of the pipe.
However, the complete blockage of the fluid conduit upstream of the work area may lead to back pressures being developed which may require extreme pressures to be developed when securing such a plug in the conduit or pipe. Such pressures often require relatively high torques to be developed with the tools used to secure the plug, as well as relatively fixed diameters for the solid elastomeric plugs generally used.
The need arises for a fluid pipe or conduit repair tool, which tool provides for the passage of at least some fluid through the center of the tool while at the same time serving to prevent fluid from flowing along the interior walls of the pipe itself. The tool should provide relative flexibility due to the relatively low pressures required for sealing, and thus provide sealing capability for a wide range of pipe or conduit inside diameters with a relatively few tool sizes.